1. A display panel for a display device, comprising:
a substrate;
a first halftone dot layer formed with halftone dots printed in a gradation pattern on the substrate so that brightness gradually changes; and
a second halftone dot layer formed with halftone dots printed in a gradation pattern on the substrate so that brightness gradually changes, wherein
the first halftone dot layer and the second halftone dot layer are arranged in parallel to each other yet rotated relative to each other by a predetermined angle measured between directions in which the halftone dots are aligned in the first and the second halftone dot layers.
2. The display panel according to claim 1, wherein:
each of the first and the second halftone dot layers has a contact region in which adjacent halftone dots are connected with each other, a non-contact region in which adjacent halftone dots are apart from each other, and a tone jump boundary between the contact and the non-contact regions; and
the first and the second halftone dot layers are arranged in a manner that the tone jump boundaries of the first and the second halftone dot layers lie at different positions.
3. The display panel according to claim 1, wherein the predetermined angle is between 10 degrees and 40 degrees inclusive.
4. The display panel according to claim 1, wherein the first and the second halftone dot layers are arranged at least a predetermined distance away from each other in a direction perpendicular to a surface of the substrate on which the halftone dots are printed.
5. The display panel according to claim 1, further includes a light diffusion layer arranged in parallel to the first and the second halftone dot layers for diffusing and reflecting light.
6. The display panel according to claim 5, wherein:
the substrate is made of a translucent material;
the substrate is formed with light diffusing materials for diffusing and reflecting light; and
the light diffusion layer is formed in the substrate with the light diffusing materials.
7. The display panel according to claim 5, wherein the light diffusion layer is formed by printing a diffuse reflection layer with ink that contains light diffusing materials.
8. The display panel according to claim 5, wherein the light diffusion layer is formed by unevenly fishing at least one of the surfaces of the substrate.
9. The display panel according to claim 1, wherein the first and the second halftone dot layers are backlighted so that light passes through the first and the second halftone dot layers from back surfaces to front surfaces.
10. The display panel according to claim 1, wherein the display panel is used together with a light source in a display device for a vehicle.
11. The display panel according to claim 1, wherein the halftone dots included in the first halftone dot layer are different in color from the halftone dots includes in the second halftone dot layer.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An illuminating device comprising:
a plurality of light emitting elements constituting light emitting parts extending in a lengthwise direction; and
a single light guide plate formed over the plurality of light emitting units having a first principal surface for emitting light originated from the light emitting elements as illuminating light and a second principal surface facing the first principal surface, the light guide plate having a plurality of light guide regions corresponding to the plurality of light emitting elements,
wherein the plurality of light emitting elements are arranged to overlap with the light guide plate on a side of the second principal surface of the light guide plate in plan view,
wherein the side of the second principal surface of the light guide plate is provided with
first sectional surfaces, on which light originated from each of the plurality of light emitting elements is incident and each of which is substantially perpendicular to the first principal surface or the second principal surface, corresponding to the plurality of light emitting elements, and
second sectional surfaces, each of which is disposed adjacent to the first sectional surface so as to face obliquely to the first sectional surface and has a reflection surface for reflecting the light originated from each light emitting element and outside of light guide plate toward the first sectional surface and into the light guide plate, each reflection surface corresponding to a corresponding one of the plurality of light emitting elements,
wherein the first sectional surfaces and the second sectional surfaces extend in the lengthwise direction of the light emitting elements, and each light emitting part of the light emitting elements and each second sectional surface are disposed so as to overlap with each other in plan view,
wherein the plurality of light emitting elements are disposed below the entire second sectional surface,
wherein a plurality of first reflection layers are disposed on the second sectional surfaces and a plurality of second reflection layers are disposed under each of the plurality of light emitting units so as to overlap the light emitting elements in planar view, and
wherein the first reflection layers and second reflection layers are formed opposite to each other with each of the corresponding light emitting elements being formed between a corresponding first reflection layer and second reflection layer.
2. The illuminating device according to claim 1,
wherein the second sectional surface is disposed to face obliquely to the light emitting part of the light emitting element.
3. The illuminating device according to claim 1,
wherein the second principal surface of the light guide plate is provided with opening portions by the first sectional surfaces and the second sectional surfaces, and each opening portion is formed in accordance with a length of the light emitting part of the light emitting element in the lengthwise direction and a width of the light emitting part in a widthwise direction crossing the lengthwise direction.
4. The illuminating device according to claim 1,
wherein the plurality of light emitting elements are disposed such that a center of the light emitting part and a center of the opening portion substantially coincide with each other in plan view and face each other.
5. The illuminating device according to claim 1,
wherein the opening portions are continuously formed so as to be adjacent to each other in the lengthwise direction.
6. The illuminating device according to claim 1,
wherein the opening portions are formed in a staggered array so as to separate from each other in the widthwise direction and so as not to be adjacent to each other in the lengthwise direction.
7. The illuminating device according to claim 1,
wherein a reflection layer for reflecting light originated from the light emitting element is formed on the second principal surface.
8. The illuminating device according to claim 1,
wherein light shielding units are formed on the first principal surface of the light guide plate in adjacent portions between the first sectional surfaces and the second sectional surfaces in the opening portions so as to cover the adjacent portions.
9. The illuminating device according to claim 1,
wherein the light emitting element is an element emitting light by applying current between a pair of electrodes formed with a thin film function layer, which includes at least a light emitting layer and is formed on a substrate, interposed there between.
10. The illuminating device according to claim 9,
wherein a width of the light emitting part in the widthwise direction does not exceeds a width of the opening portion in the widthwise direction.
wherein a reflection film for reflecting light originated from the light emitting element is formed on a region, which overlaps with the opening portion in plan view, on the substrate other than at least the light emitting part.
11. The illuminating device according to claim 9,
wherein the plurality of light emitting elements is formed on one sheet of the substrate.
12. The illuminating device according to claim 1,
wherein the light emitting elements have substantially identical lengths in the lengthwise direction, and are divided into a plurality of the light emitting parts in the widthwise direction, and the plurality of the divided light emitting parts are elements for emitting light of mutually different colors.
13. The illuminating device according to claim 1,
wherein the light emitting element is an organic EL element.
14. The illuminating device according to claim 13,
wherein the organic EL element is a top emission type element for emitting luminescent light toward a side opposite to the substrate.
15. The illuminating device according to claim 1,
further comprising protective members covering the light emitting elements,
wherein the protective members are provided with positioning units for specifying planar positional relationship between the divided light guide plates and the light emitting elements.
16. A liquid crystal display apparatus having a display region for displaying an image obtained by optically modulating illuminating light through liquid crystal, the apparatus comprising:
the illuminating device according to claim 1 as an illuminating device which is disposed to face the display region and emits the illuminating light.